PMID- 8317266
OWN - NLM
STAT- MEDLINE
DCOM- 19930729
LR  - 20041117
IS  - 0065-1400 (Print)
IS  - 0065-1400 (Linking)
VI  - 53
IP  - 1
DP  - 1993
TI  - MU firing characteristics in human dystrophic muscle.
PG  - 313-8
AB  - During isometric contractions of constant force surface EMG as well as 
      intramuscular MU potentials from extensor digitorum communis and biceps brachii 
      muscles were recorded on magnetic tape for further off-line analysis. Surface EMG 
      power spectra were computed and transformed so as to reveal low-frequency peaks 
      which might correspond to MU firing rates. From intramuscular recordings, single 
      MU action potentials were identified with an aid of semi-automatic recognition 
      program. For each single MU action potential train (MUAPT) statistical parameter 
      of interspike intervals (ISIs) were determined and related to the measured muscle 
      force level. Sixty four MUAPTs from 9 patients and 55 MUAPTs from 4 normals were 
      analysed so far. The estimates of MU firing rate from surface and needle EMG 
      corresponded well to each other. The MU firing rates were higher in muscular 
      dystrophy and this difference was more pronounced for higher levels of muscle 
      force. The tendency towards mean MU firing rate increase is stronger for the 
      patients with more advanced disease. The typical dependency of standard deviation 
      of ISIs on their mean value may be approximated by two lines of different slope. 
      There were reported experimental data indicating that the breaking point of this 
      dependency may be an estimate of AHP duration in motoneurones. Our results for 
      dystrophic muscle showed a shift of this point towards shorter ISIs, as compared 
      to normals. This suggests that in muscular dystrophy also motoneurones may be 
      altered, either by the disease itself or as a compensation for changes in 
      muscular part of a MU.
FAU - Piotrkiewicz, M
AU  - Piotrkiewicz M
AD  - Institute of Biocybernetics and Biomedical Engineering, Warsaw, Poland.
FAU - Filipiuk, M
AU  - Filipiuk M
FAU - Hausmanowa-Petrusewicz, I
AU  - Hausmanowa-Petrusewicz I
LA  - eng
PT  - Journal Article
PL  - Poland
TA  - Acta Neurobiol Exp (Wars)
JT  - Acta neurobiologiae experimentalis
JID - 1246675
SB  - IM
MH  - Humans
MH  - Isometric Contraction/physiology
MH  - Motor Neurons/*physiology
MH  - Muscles/innervation/*physiopathology
MH  - Muscular Dystrophies/*physiopathology
EDAT- 1993/01/01 00:00
MHDA- 1993/01/01 00:01
CRDT- 1993/01/01 00:00
PHST- 1993/01/01 00:00 [pubmed]
PHST- 1993/01/01 00:01 [medline]
PHST- 1993/01/01 00:00 [entrez]
PST - ppublish
SO  - Acta Neurobiol Exp (Wars). 1993;53(1):313-8.